Mining companies often sit on mines, not because they're trying to manipulate the market, but because the mineral isn't economic to extract yet. You can, for ex

Mining companies often sit on mines, not because they're trying to manipulate the market, but because the mineral isn't economic to extract yet. You can, for example, buy a gold mine today where the cost to extract gold is $2000/oz, and wait until the price goes above that before starting operations.